VINEGAR FROM VARIOUS MATERIALS. 157 



The preparation of the fundamental material, malt, requiring 

 much labor and knowledge, it will be best for the manufacturer 

 to buy the article already prepared. Malt kiln-dried at as low a 

 temperature as possible and yielding a light-colored extract when 

 treated with warm water should be chosen. Many malt houses 

 prepare such malt especially for distilling purposes. Malt pre- 

 pared for brewing purposes is after the actual kiln-drying heated 

 to a temperature frequently exceeding 158 F. for the formation 

 of certain aromatic combinations and coloring substances which 

 arc to impart to the beer a specific taste and dark coloration. 

 Independently of the dark color of the vinegar prepared from such 

 malt, it contains a considerable quantity of dextrin and conse- 

 quently acquires an insipid by-taste, clarifies with difficulty, and 

 is readily subject to injurious alterations. Malt, as is well known, 

 contains diastase, which in mashing the malt with water effects 

 the conversion of the starch into maltose and dextrin. By kiln- 

 dry ing at a very high temperature a portion of the diastase is, 

 however, rendered ineffective, and in mashing comparatively little 

 maltose but a large quantity of dextrin is formed. Mashing, in 

 this case, would have to be continued for a long time in order to 

 obtain a larger quantity of maltose. 



With the use of but slightly kiln-dried malt, in which the effi- 

 cacy of the diastase has not been injured by a high temperature, 

 the greatest directly obtainable quantity of maltose and the 

 smallest amount of dextrin are procured. The proportion of 

 maltose to dextrin is in this case as 4 : 1, or, in other words, the 

 finished mash contains about 80 per cent, of maltose and 20 per 

 cent, of dextrin. The dextrin cannot be directly converted into 

 acetic acid by the vinegar ferment and consequently would be 

 found in the finished product. It is, however, possible to treat 

 the finished mash in such a manner that the total quantity of dex- 

 trin contained in it can be converted into maltose and the latter 

 into alcohol. In this case the theoretically calculated yield of 

 vinegar from the malt will be nearly approached in practice, and 

 the product thus obtained contain only a small quantity of ex- 

 tractive substances of the malt which are not decomposed by 

 alcoholic or acetous fermentation. 



Before entering upon a description of the mashing process, 



